This invention relates to a heat transfer system, and more particularly to a heat transfer system that selectively uses the heat transfer medium to heat or cool different areas of the building and the building appurtenances as conditions dictate.
Conventional heating and cooling systems used in buildings, whether residential, commercial or industrial, principally utilize separate units to provide heating and cooling. When heating is desired, air is fed through a central heating unit in which the air is heated to the appropriate temperature utilizing natural gas, electricity or even heating oil. When cooling is desired, air is fed through an air conditioning unit in which the air is cooled to the appropriate temperature by having the air come into contact with and pass over refrigerant coils that contain a refrigerant that has been cooled by running the refrigerant through a condenser. Building appurtenances, such as swimming pools, jacuzzis, clothes washers, dishwashers and shower units are also provided with hot water from hot water tanks or separate independent heating units in which the water is heated using natural gas or electricity. It is not unusual on a typical summer day in most cities to find the inhabitants of a building running the air conditioner to cool the interior of the building. At the same time the pool heater is being utilized to add hot water to either the swimming pool or the jacuzzi to increase the temperature of these building appurtenances to make their use more comfortable. The hot water tank is also being used to heat water for use in clothes washers, shower units and dishwashers.
Conventional building air conditioning cooling systems are unable to utilize the heat removed in the air conditioner to heat the water being passed through the hot water tank, the swimming pool or the jacuzzi. The heat removed from the air passing through the air conditioner is simply vented to the outside thus wasting any heat value that may exist therein. Public energy utilities are often taxed to their capacity to provide the power necessary to operate both the building's air conditioner and the building's appurtenant uses.
Because of the growing scarcity of fossil fuels and the ever increasing cost of electricity, much research and development has gone into developing alternative ways to heat and cool a building, as well as providing hot water for the building appurtenances. Solar heating systems have become a favorite candidate for research because the energy from the sun can be considered a virtually inexhaustible supply.
One particular system for heating and cooling using solar energy is disclosed in U.S. Pat. No. 4,722,197 to McEntire. This system uses Freon.RTM. 502 as the refrigerant heat transfer medium. The heat transfer medium passes in a unidirectional flow through ambient energy absorbing panels 12 in which the medium is heated to a gaseous state. The gaseous medium leaves the panels 12 and goes to a compressor 18 in which the medium is compressed into a liquid state. The hot liquid medium is then sent to one or both of two heat exchanger coils 22 and/or 26 where the heat in the hot liquid medium is transferred to water. The exiting cooler medium is then collected in a receiver 30. The heat transfer medium in the receiver 30 is then sent to a precooler 32 where the medium is air-cooled further by a fan 34. The medium is then sent through an expansion valve 38 where the medium expands and vaporizes, resulting in a further drop in temperature. The medium, now again in the gaseous state but at a lower temperature, is passed through a third heat exchanger 40 where the heat from inside air is transferred to the medium, thus cooling the inside air for air conditioning. The gaseous medium leaving the third heat exchanger 40 is passed back to the panels 12 to absorb more heat. If air conditioning is not desired, the hot liquid medium in the receiver 30 can be sent directly to the panels 12 for reheating. Alternatively, the first heat exchanger 22 and/or the second heat exchanger 26 can also be bypassed with the medium going directly into receiver 30 and from there into the third heat exchanger 40.
The system disclosed in the McEntire patent at all times passes the heat transfer medium through the panels 12. Thus on hot summer days, the heat transfer medium is always subjected to additional heating from the panels which inhibits the ability of the heat transfer medium to remove heat from the inside air to effect air conditioning of the building. The panels 12 are not segregated in a way that would permit selective utilization of either all or only a part of the panels 12.
There are no temperature controls on the heat transfer fluid as it leaves the panels 12--if the heat transfer fluid leaving the panels is too high in temperature, such would effect the ability of the compressor to operate properly. Furthermore, the use of the precooler 32 is an additional draw on external energy supplies to operate the system and decreases the system's efficiency.
The system of the McEntire patent also does not have a priority control system that will allow the system to be selectively biased to always ensure that hot water for the showers, clothes washer and dishwasher is always available before heated water is provided to a pool.
It is an object of the present invention to provide a unidirectional heat transfer system that systematically utilizes heat values stored in a heat transfer medium to selectively provide hot water to a hot water tank, a swimming pool, a jacuzzi or a room space heater as each of those uses so demand to be supplied. Separate hot water supplies are utilized to maintain potable water separate from non-potable water as is required by most building codes. The heat values to be put into the heat transfer medium can be obtained from environmental panels or from the heat obtained from the building during the air conditioning cycle. It is a further object of the present invention to provide a priority system to ensure that hot water is always available first for particular appurtenant uses before the hot water is made available for uses lower on the priority. The control system also permits changing the priority at the whim of the user.
It is a feature of the present invention that a heat transfer medium is provided with heat values from either ambient environmental panels or from the hot air inside the building. The heat transfer medium is used to cool the air as it passes through air handlers and then this cool air is sent throughout the building to air condition the building. The heat values obtained during the cooling of the air are retained in the heat transfer medium. The heat transfer medium is then used to transfer these heat values to either potable or non-potable water supplies which are then selectively passed to those areas and appurtenances of the building that require heating. The entire system operates in a unidirectional mode and utilizes an electrical control system that automatically senses the needs of the building and its appurtenances for heating and cooling, and operates based on a user-selectible priority basis to ensure hot water is available for higher priority uses before it is made available for lower priority uses.
It is an advantage of the present invention that heat generated either by the ambient environment or from the hot air which is being drawn through the air conditioning system of the building can be utilized as a source of heat to provide heat values to a heat transfer medium that is then used to heat water for a hot water tank, a swimming pool, a jacuzzi or a room space heater. Only as a last resort is heat passed to the outside of the building and not used in the system. The heat transfer medium also is used to cool air that is being used for air conditioning of the building. The heat transfer medium flows through the system in a unidirectional mode which eliminates the requirements of reversing valves that are necessary in the traditional heat pump systems.
The system of the present invention will lower heating and cooling costs for a typical building having the basic appurtenances in use today. Heat values are not wasted but rather transferred from one area of the building where they are not needed or wanted to other areas of the building where the demand exists.